Slide-rule.



G. W. RICHARDSON.

SLIDE RULE.

APPLIOATION FILED APILS, 1911.

Patented Mar. 26, 1912.

GEORGE W. RICHARDSON, 0F `GHICAGO, ILLINOIS.

A Specication of Letters Patent.

. SLIDE-RULE.

' Patented Mar. 26, 1912.

Application led ,April 3, 1911. Serial No. 618,634.

To aZZ whom z'may concern Be it known that I, GEORGE W. RICHARD- SON, a citizen of the United States, residing at Chicago,in the county of Cook and State of Illinois, have invented@ certain .new and useful Improvements in Slide-Rules, of which the following is a specification.

My invention relates to slide rules, and refers particularly to .instruments of that type in which a rectangular slide is adapted to be moved relatively to fixed scales mounted on a supporting member termed the stock.

xThe primary objects of the improvements which constitute the subject matter of this application for patent, are; to provide a simple, durable and efiicient construction for a slide rule.

- An important feature of this invention is observable in the material employed, the main portions of the instrument being constructed of metal, which isnot affected by relative degrees of moisture, thus avoiding the serious objection to the use of wood, which has been the material universally employed in`devices of this class, and as this substance is subject to constantl shrinking and swelling from atmospheric changes, there is a frequent interference with the free movement of the slide causing inconvenience and annoyance which impairs the usefulness of the instrument.

By-making the frame or supporting memf bers of sheet metal which can be readily formed in presses, the cost of manufacture tobe retained in adjusted position under ordinary circumstances.

Especial attention has been given to the construction of an efficient runner, provision being made in this member, also, for reducing friction, producing a smooth gliding movement .that permits a quick sett-ing ofv the device to the required position. I

It is also an object of this' inventlon to facilitate the quick adjustment and accurate the operator to speedily arrive at the ref quired results in working a large variety of problems, without the necessity of having a profound knowledge of the mathematical principles involved therein, the means employedy for this purpose being the formation of one or more aperturesv or keyholes in the fixed scale-s, and supplying the slide, which reciprocates beneath the said scales, wlth arbitrary signs or characters, so ar'- ranged that they may be brought successively into View through said keyholes, such an arrangement being clearly shown and described, and the manner of using the rule so equipped thoroughly explained' in my former application for slide rules, for which Letters Patent of the United States, No. 983,876, were issued to me January 31, 1911.

I accomplish the desired results `above enumerated, and others of importance, by

ves

employing .the apparatus illustrated in the A accompanying drawing, which forms a part of this application, the details ofI construction being disclosed in the following views:-

Figure 1 is a plan view of a complete slide rule embodying'my improvements; Figs. 2 and 3 are sectional views, enlarged, taken on the lines 2-2 and 3-3 respectively, of Fig. 1; Fig. 4 is a longitudinal section of the runner, the cutting plane passing through one of the frame sides, and Fig. 5 is an enlarged view of the stock seen in transverse section.

Referring to thedetails of the drawing, the numeral 6 indicates the main supporting member, or stock, which is made of sheet metal by the process of stamping or by any other suitable method. I prefer to employ aluminum for this and lother parts of the instrument, since this metal presents useful properties not found in other materials, making it particularly advantageous, its light weight and non-corrosive properties especially rendering it preferable to other metals. For these .and other reasons it 1s much tobe preferred to wood which is usually employed in devices of this class. The said stock is formed from a rectangular piece of sheet aluminum ofiy suitable gage, the lateral portions of which are bent toward the upper side, forming flanges 7,' having their margins bent outward, as indicated at 8, and then bent inward, as shown at 9, forming grooves 10 in which are inserted l edges of fixed scales 11. These scales consist of strips of celluloid upon which are imprinted the usual graduations 12, necessary for the mathematical computations for which therule is adapted. The said scales are permanently secured by clamping the margins of the stock firmly thereon by compression. I prefer to provide the main portion of the stock with longitudinal corrugations 13, which are preferably located at the junction of the flanges with the body of the plate, as shown in the drawing,although they may be formed at any suitable place. The purpose of these corrugationsis primarily to st-iffen the plate or strip, rendering itmore rigid and capable of resisting any tendency to bend or buckle from accident or rough usage. In addition to the reinforcing feature these ribs or corrugations serve to protect the printed matter which is placed upon the backof the stock from becoming abraded orv e'aced from constant handling or by cont-act with the desk or table upon which itis laid. In the form shown the corrugations are so located as to form grooves or seats for the margins of a convex slide member 14. I prefer to make this p-art of aluminum, having recurved margins, as indicated at 15, forming longitudinal grooves 16, adapted to receive lthe edges of a scale bearing member 17, formed of a strip of celluloid, superposed upon the convex upper surface of the slide 15, and having imprinted thereon suitable graduations 18. The sides of the groove 16 are compressed upon t-he inserted edges of the member 17, thus holding the' two members forming the 'slide proper firmly together.

The upper surface of the slide is in contact with the under surfaces of the overhanging fixed scales 11` and the margins of the latter are beveled, or chamfered, upon the under side where they lie in contact with the slide, as shown at 19, this thinning of the scale edges bringing the face of the 'slide more clearly on a level with the graduated surfaces of the scales and thus facilitating an accurate comparison of t-he`corresponding graduations by lessening the parallax. The rounded margins formed by the turned edges` of the-slide are adapted to engage the grooves or corrugations 13 so as. td have a free movement therein, the contact; with the flanges 7 being of sufficient extent to form an eiicient guide for the slide. By incasing s the celluloid plate 17 in metal in this way, it is held firmly supported so as to prevent bending or kinking, this manner of clamping also preventing any shrinkage from atmospheric changes or'the lapse of tim`e. At suitable points in each of the .strips forming the fixed scales 11, I form. apertures or keyholes 20, and upon that portion of the upper surface of the slide lying beneath the scales are linearly arranged series of characters or keys'21, so positioned as to successively register with said apertures to permit the keys to be seenv therethrough.

In order to facilitate the reading 'of the scales, I employ a runner of special construction, which is use with the metallic stock hereinbefore dearticularly adapted for scribed. This runner comprises a rectangullar frame or pla-te 22, formed of a single piece of sheet metal of a desirable degree of resiliency and having a cent-ral aperture 23 cut therethrough. The endsof the. frame thus formed are provided with projecting lips 24, which are bent in the'mannershown frame and prevents any contact between the metal of the runner and that o-f the stock.

The said celluloid plate has lips similar to the lips 24 on the frame and adapted to form linings therefor. This manner v of construct-ing the runner with the anti-friction bearing plate 25, insures a smooth and even movement when the runner is slid along the stock, and prevents the rough and uneven motion which would result if the similar met-als were allowed to be in contact.

This form. of runner also permitsme to dispense with a spring, which has heretofore been required in connection with. runners as usually arranged;y The frame 22and its transparent lining 25are`held together by ears 26 which are struck vfrom the metal of the frame and bent downward through, suitable holes formed by the celluloidplate 25, and then clamped rbyLcOmpresSion ofthe latter, as shown in the drawing. The linin pla-te 25, being transparent, the figures 'an graduations upon the scales and. slide beneath ma-y be readily observed therethrough and to enable the readings tobemade'quickly and 4accuratelythe,usual index or hairline 2(15 is marked longitudinally upon the said ate. pp fHaving thus described vmy invention, what I claim as new, is l 1. In a slide rule, the combination 'with a stock having ,parallel upturned marginal anges, and scales fixed on said flanges, of a resilient curved slide arranged between said scales and the stock and having its comprising a plurality of superposed plates.,

5. In a slide rule, the combination with a stock, and parallel scale bearing -members fixed thereon, of a resilient curved slide arranged below said members, and a resilient laminated runner mounted onv said stock.

` 6. In a slide rule, the combination of a stock having raised margins, parallel scale bearing members fixed thereon, anslide arranged below said members, turned margins on said slide, and a resilient scale bearing member having its edges engaging said turned margins. l y

7. In a slide ruler the combination with a stock, of aslide comprising a plate having a` convex upper surface, turned margins on said plate forming grooves, and a res1l1ent scale bearing member having` its edges engaging said groove. l y

8. In a slide rule, the combination with a stock, of a slide comprising a plate having a convex .upper surface, turned margins on said plate forming grooves, and a resilient scale bearing member superposed upon said plate and having its edges engaging said grooves, said scale bearing members being in contact with the plate at'the margins only.

9. In a slide rule, the .combination with a stock comprising a plate, marginal flanges on said plate, parallel scale bearing strips engaging said flanges and having their approximated edges chamfered, a resilient scale arranged to make contactI with said chamfered edges, a slide mounted between said flanges, and means for clamping said scale, sald clamping means conslsting of turned margins on said slide adapted to clamp the edges of the scale.

10. In a slide rule, the combination with a stock having raised margins, and scales attached to the stock along one edge and having the other 'edge chamfered, of a curved -slide arranged beneath .said scales and in contact with said chamfered edges,

gage the margins of said scales, and longitudinal corrugations adapted to form seats to receive the edges of said slide.

12. A laminated runner for a slide rule, comprising an apertured aluminum plate having project-ions adapted to clasp the margins of the stock, a .transparent Celluloid plate Vsecured to the under surface of said apertured plate and co-extensive therewith, and means for securing said plates in fixed relation to each other.

13. In a slide rule,the combination with a stock and scale bearing members attached thereto, of a slide arranged beneath said members, said slide comprising two superyposed curved plates, one of said plates being made of aluminum and having grooves in its margins, and the other plate formed of Celluloid' and having its edges engaging said grooves, said'plates being spaced apart intermediate their margins.

14. In a sliderule, t-he combination with a stock having raised margins forming a channel, of a resilient slide consisting cfa supporting strip of sheet material curved longitudinally and having its marginsv frictionally engaging the sides of said channel, and a superposed resilient4 scale bearing plate secured to said strip and spaced therefrom intermediate its lateral margins.

15. In a slide rule, the combination with a stock having raised margins forming a channel, of parallel scale bearing members secured to the margins of the stock and having their free edges chamfered, a resilient curved plate having its margins frictionally engaging the sides of said channel and movable therein,' a resilient scalel bearing plate superposed upon the said curved plate and spaced therefrom intermediate its margins, said scale bearing plate being in frictional contact with the chamfered edges of the first mentioned scale.

In testimony whereof I have fixed my signature in the presence of two witnesses.

GEORGE W. RICHARDSON. Witnesses:

A. RICHARDSON, HENRY MIBKELLY. 

